I was poking around the driver for their WiFi card to investigate something. Then, I realized that they completely replace the sharp_sdmmc kernel module with their own SD/SDIO stack. So just for fun, I installed it and surprise, I can now read, write, and mount a Sandisk 2 GB SD card. So far, it's been working very reliably.

Now, the catches:

1) It works fine on my C760 (running Cacko 1.12). But, when I tried to install the modules on my 6000, I got kernel oopses. So, it may be very sensitive to the model/kernel that is running. This is not that surprising since C760 is one of the few models listed as supported on their website.

2) vfat filesystems are fine. I had some problems with ext2. I fixed it by reformatting my card with "mke2fs -b 1024 /dev/mmcda1". This driver doesn't seem to like block sizes > 1024.

Anyway, if you want to repeat my experiment, just download and install this ipk, and reboot the Zaurus: